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  1. #1
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    Default 1981 GS450 Tracker Project

    Hello again yall. I have not posted here in some time. I still follow build projects and good to see you guys are still pretty active on here. Love seeing new builds. I still use this site for inspiration, as i just got back into building on my project that has been sitting for a while. I will be posting pictures soon.

    My main reason for posting, is in hopes someone has a resolution for my issues.

    My project, Lucille, is in process of a change from a Cafe racer to a tracker style. While i was working on cleaning and prepping the carbs, cylinders, electronics, etc. i seem to have come across an unusual issue with my acceleration.

    I am running a 2-1 exhaust, dual 2-stage UNI's for the filters.

    So after getting everything cleaned, tank was cleared of the surface rust after sitting. Cleaned the petcock, carbs, and gaslines. All of this seems to be clean. I have good compression and spark on the plugs from both sides. But there seems to be an issue with one cylinder firing really hot and cutting out really bad. To the point that the idle is super low after warming up. I cleaned up the spark plugs and verified again that spark was good. Both carbs are getting gas and i know the floats are working. But when i hit the throttle it accelerates very slow, and once i get moving, its as if one side is not firing. Then BOOM it accelerates hard for a split second, and bogs down to a slow acceleration again. I cannot find any airleaks that i can see. I tried spraying the boots connecting the carbs to the engine, but it does not rev when sprayed from either side.

    So i accelerated downhill and dropped the throttle closed and came to a halt to check the plugs. One is white(the problem cylinder), and the other is almost a perfect Tan/brown.

    Could this still be an air leak on that carb that i am not seeing, or could this be a timing issue?

    Fully open to suggestions as this has just become a frustrating pain in my ass. I checked and verified i have all matching jets(in case i put the wrong size in one). The diaphragms for the slide has no holes and the needles are all straight....

  2. #2
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    Did you do a thorough service on it to confirm valve clearance, ignition timing both at idle and full advance, and that carb settings are correct, all jets are tight and no carb jet or needle o-rings are missing?

    Can you observe the CV slides in operation at different throttle openings? Any difference with uni-filters removed - they could be blocking an airway due to how they mount. Got a vacuum-operated petcock that has a vacuum hose from one carb or intake manifold? Check that too.

    What about your coils and wires? Got condensors as part of your ignition system? Could be a cause of breaking down.

    What is your compression reading with WOT and slides up? Wondering if ya got a blown head gasket.

  3. #3
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    I have not cracked into the engine so i cannot confirm valve clearance, or ignition timing.
    Carb settings, jets, and o-rings all confirmed in good placement. Both slides seem to be working in tandem from what i can tell. No change when filters are removed. I may need to check the hose on the Petcock again, as i don't remember seeing any holes or damage. But i could be wrong. Coils and wires seem in good health. The wires are only about 3 maybe 4 years old, but the coils could probably stand to be replaced but seem to be working. No condensers. I will grab the exact Compression readings when i get back to the shop this weekend but they were both reading around ~150. I do need to change the gaskets soon. I just wouldn't have expected this soon. They are around 5 years old with minuscule drive time since then.

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    Quote Originally Posted by CupidsDeathDay View Post
    I have not cracked into the engine so i cannot confirm valve clearance, or ignition timing.
    Carb settings, jets, and o-rings all confirmed in good placement. Both slides seem to be working in tandem from what i can tell. No change when filters are removed. I may need to check the hose on the Petcock again, as i don't remember seeing any holes or damage. But i could be wrong. Coils and wires seem in good health. The wires are only about 3 maybe 4 years old, but the coils could probably stand to be replaced but seem to be working. No condensers. I will grab the exact Compression readings when i get back to the shop this weekend but they were both reading around ~150. I do need to change the gaskets soon. I just wouldn't have expected this soon. They are around 5 years old with minuscule drive time since then.
    "No condensers. "
    Find the points.
    Better yet order a Clymers workshop manual.

  5. #5
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    So after some investigation and testing on the Cylinders, i seem to have a head gasket leak.... My previous statement on the compression was incorrect, it was much lower on the left cylinder than i thought. Looks like i will have to pull the top end apart, replace gaskets, and verify everything is good. Probably gonna hone the cylinders while im at it. This is gonna be a long fall/winter... This sucks!

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